Active subscribers shows you the total numbers of subscribers with paid subscriptions at the end of each interval (e.g. month). It is one of the most important SaaS metrics, as it allows you to see at a glance how your efforts to reduce churn and acquire new customers is trending.
Subscribers are counted as "active" if they have at least one subscription which is "active". We count any subscription as "active" which has at least one invoice paid and which is in the status=active and status=past_due states. Trial and delinquent subscriptions that have progressed to the status=unpaid are excluded. Learn more about subscription states here.
If your business sells exactly one subscription per customer, then this metric would also correspond to the total number of active subscriptions.
A new subscriber is a new paying customer who starts at least one new active subscription, upgrades from a free subscription to a paid subscription or converts a trial to a paid subscription. Note that when the trial subscription ends for a customer without a saved payment method, the subscription briefly moves from status=trialing to status=active, until the first invoice fails payment and the subscription becomes status=past_due.
This occurs when an existing subscriber cancels, downgrades to free, pauses or becomes delinquent on all existing active subscriptions. That subscriber is then counted as churned.